|Abstract or Summary
- Two cultivars of tall fescue (Festuca arundinacea
Schreb.) with contrasting growth habits were studied under
field and growth chamber conditions. Fawn, an established
cultivar since 1964, and TFM, an experimental line, were
observed to grow better during spring and fall months
respectively, in the field. Different temperature regimes
of 10/4, 16/4, 27/10, and 32/16°C were employed to study
the effect of temperatures on the growth and biochemical
characteristics of these two cultivars.
Fawn was significantly greater than TFM across the
three harvests in dry matter production. There were no
significant differences between Fawn and TFM in watersoluble
carbohydrates (WSC) across the three harvest material.
During the seven month period, there were also no significant differences in water-soluble carbohydrates and
crude protein between the two cultivars. Stems had a
higher concentration of WSC but were lower in crude protein
than leaves in both cultivars.
Fawn also produced more foliage dry matter (for the
first and second harvests) across all temperatures tested.
In regrowth, TFM and Fawn grew better at low and high
temperatures respectively. This was expected on the basis
of field results. Fawn was significantly greater than TFM
in WSC and free sugars in both the first and second harvests
and in the regrowth but in percent fructosans there
were no significant differences between cultivars. TFM
was significantly greater than Fawn in percent crude protein
in both first and second harvest and regrowth. Temperature
affected crude protein and WSC content as temperature
increased, WSC, fructosan, and free sugars content
decreased. Fructosans were lower in the regrowth material
than either the first or second harvest. Percent crude
protein in the foliage dry matter increased as temperature
increased except in the regrowth where the lowest and
highest temperatures showed the highest concentration.
Tillering was higher in Fawn, and the most favorable
temperature for both cultivars was at 16/4°C.
Root dry weight was lower in Fawn, however, the concentration
of WSC, fructosans, and free sugars in the roots
were higher in Fawn than TFM. These sugar components were lower in the root material than in the foliage or regrowth
There were no differences in the mean relative growth
rate between cultivars, although Fawn was highest at the
high temperatures, with TFM being higher at the three
There were no differences in net carbon exchange in
the light or gross photosynthesis between these two cultivars,
but Fawn was significantly greater in dark respiration
at the highest temperature. Dark respiration and
gross photosynthesis were higher at the highest temperatures
in each cultivar.
TFM was significantly higher than Fawn in leaf area
at the lower temperatures, but leaf area was lower at the
highest temperature for both cultivars.
Fawn was significantly higher than TFM in perloline
content across temperatures. In both cultivars, the
higher temperatures had higher perloline content.